Dynamics of semi-flexible polymer solutions in the highly entangled regime

Abstract

We present experimental evidence that the effective medium approximation (EMA), developed by D.C. Morse [Phys. Rev. E {\bf 63}, 031502, (2001)], provides the correct scaling law of the macroscopic plateau modulus $G^0\propto {\rho }^{4/3}{L}_p^{-1/3}$ (where $\rho$ is the contour length per unit volume and $L_p$ is the persistence length) of semi-flexible polymer solutions, in the highly entangled concentration regime. Competing theories, including a self-consistent binary collision approximation (BCA), have instead predicted $G^0\propto {\rho }^{7/5}{L}_p^{-1/5}$. We have tested both the EMA and BCA scaling predictions using actin filament (F-actin) solutions which permit experimental control of $L_p$ independently of other parameters. A combination of passive video particle tracking microrheology and dynamic light scattering yields independent measurements of the elastic modulus $G$ and $L_p$ respectively. Thus we can distinguish between the two proposed laws, in contrast to previous experimental studies, which focus on the (less discriminating) concentration functionality of $G$.

4 pages, 6 figures, Phys. Rev. Lett. (accepted)

References in corpus (4)

• Elasticity of Semiflexible Biopolymer Networks
• Entanglement, elasticity and viscous relaxation of actin solutions
• Dynamic Scattering from Solutions of Semiflexible Polymers
• Chain motion and viscoelasticity in highly entangled solutions of semiflexible rods

Cited by in corpus (13)

• Tuning Synthetic Semiflexible Networks by Bending Stiffness
• Effective Medium Theory of Filamentous Triangular Lattice
• Tube Width Fluctuations in F-Actin Solutions
• Non-local fluctuation correlations in active gels
• The Role of Stickiness in the Rheology of Semiflexible Polymers
• Dynamic structure factor of a stiff polymer in a glassy solution
• Tube width fluctuations of entangled stiff polymers
• Single-shot wideband active microrheology of viscoelastic fluids using pulse-scanned optical tweezers
• In silico modeling of the rheological properties of covalently crosslinked collagen triple helices
• Transforming from time to frequency without artefacts
• Persistence length and plateau modulus of semiflexible entangled polymers in primitive chain network simulations
• Measuring the viscous and elastic properties of single cells using video particle tracking microrheology
• Evidence that self-similar microrheology of highly entangled polymeric solutions scales robustly with, and is tunable by, polymer concentration